Just what the ‘soil doctor’ ordered

With the Landfill Directive now very much in force and the Waste Acceptance Criteria rapidly approaching, the remediation industry is gearing up to cope with the new challenges of hazardous waste disposal. Paul Garrett, Regional Manager, London & SE, at Churngold Remediation Ltd, looks at new challenges facing land and property developers and describes how 'soil surgeries' gain ground

Last year’s changes in legislation and landfill classification were always expected to have an impact on the re-use of contaminated land; the problem was that no one was quite sure what the real implications would be to land owners and developers. It is now clear that the re-classification of landfill sites is having a significant effect on the way in which sites are being developed or, more specifically, how they are being remediated.

Nowhere is the impact more apparent than with small development sites. Historically, the traditional method of dig and dump was usually favoured by this sector, since the sites were often too small to make in situ remediation viable; in terms of cost of installation of remediation technologies and availability of space. With last year’s change in the law, many contaminated soil streams may well attract hazardous waste disposal rates at landfill. Alternatives to dig and dump have become a necessity, in order to ensure the economic viability of a project.

Off site ‘soil surgeries’

One alternative to both dig and dump and in situ clean up, now being offered by Churngold Remediation, which is rapidly gaining acceptance, is the concept of off site soil surgeries. These facilities receive contaminated soil and treat it prior to disposal. The concept is simple, economic and robust. Contaminated soil is removed from a developer’s site and replaced by clean fill. Churngold Remediation takes ownership of the contaminated soil, once certain criteria have been satisfied, leaving the developer with no ongoing liability for clean up. The result is a service that is as fast as dig and dump but which does not carry the high cost now associated with hazardous waste disposal.

As well as the financial benefit to the developer, transfer of ownership of the unremediated soil is also likely to appeal to landowners, contractors, environmental consultants and even Government agencies. Once the risk profile of each soil stream has been assessed by Churngold, which involves site sampling and surveying, the problem of clean up is no longer one for the developer. This means that a site can be brought into use as quickly as the development dictates. In situ remediation would inevitably take time and, depending upon the complexity of the contamination, the remediation programme could extend to several months.
By using a soil surgery – two of which have already been established by Churngold in co-operation with Cory Environmental at Himley in Dudley and St Helens – the responsibility for clean up passes immediately from the hands of the developer, the site is clean and ready to use, with all remediation liabilities having been transferred to Churngold. Soil surgery clients are provided with a full audit trail relating to the subsequent treatment and disposal of the soil. This includes a tracking system that records the soil’s history, from its original characterisation through any laboratory analysis, to post treatment and disposal information. On site analysis prior to removal to a soil surgery also ensures that any remediation targets set by the local authority or Environment Agency have been met.

Range of treatments

Once at a Churngold soil surgery, contaminated material is usually treated using bioremediation. However, with a wide range of technologies in its portfolio of in situ and ex situ treatments, the company is able to undertake whatever remediation is necessary. The company holds over 20 waste management licences, covering a variety of treatment methods. This means that a broad range of soils can be accepted at the surgeries.

One of the methods being employed to reduce soil streams to below the limits of hazardous waste landfill is Phosphate Induced Metal Stabilisation (PIMS). This is a low cost, effective treatment finding favour with soils contaminated with a cocktail of metals. Contact between the PIMS additive and the metals present results in their chemical conversion into stable, insoluble minerals. This dramatically reduces the mobility and bioactivity of the metal ions to below the leaching limit of non-hazardous waste. In addition to metals contamination, many landowners are likely to be faced with problems associated with hydrocarbon pollution. For example, the presence of hydrocarbons on brownfield sites is about to become a major issue. From July this year, any soil or waste stream containing 6% or more TOC can no longer be landfilled; even at sites which accept hazardous waste. Soil with these levels of contamination will need to be incinerated and, with costs as high as £600 per tonne, removal and treatment at a soil surgery would appear to be a good economic proposition.

While many larger developments will continue to benefit from in situ and ex situ remediation, using biological, chemical or physical treatments, the concept of soil removal and replacement coupled with the immediate transfer of liability for clean up to the remediation company, is bound to appeal to many site owners and developers. Churngold Remediation plans to expand its soil surgery service during 2005, with further sites planned to open during the coming months.

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